# Research

I am a researcher working on quantum information science and its applications to problems in physics. I am particularly interested in the intersection between physics, information, and mathematics.

How do we understand physics from the information theoretic viewpoint, and how do we make use of quantum phenomena to enhance information technology?

I am addressing these questions from a mathematical approach. Hopefully, I could contribute to understanding physics and information in a unified framework. Below are some of my research interests.

## Quantum pseudo-randomness

Quantum pseudo-randomness is a quantum version of a pseudo-random number. Quantum pseudo-randomness is known as an extremely useful resource for various quantum information processing.

On the other hand, quantum pseudo-randomness has recently been found to be closely related to quantum chaos, quantum black hole, and the foundation of quantum statistical mechanics.

Further, from the viewpoint of mathematics, many techniques are used to formulate quantum pseudo-randomness, such as representation theory, harmonic analysis, combinatorics, and so on.

I am currently working on such an exciting topic. Particularly, I am interested in the following topics, all related to quantum randomness.

- Quantum algorithms to efficiently generate quantum pseudo-randomness
- Novel quantum protocols based on quantum pseudo-randomness
- Verifications of quantum pseudo-randomness
- Exploring new physics in complex quantum many-body systems
- Mathematical foundations of quantum pseudo-randomness

## Quantum Shannon theory

Quantum Shannon theory is the theory of transmitting quantum information via a quantum channel. Although this may sound very information theoretic, any dynamics in physics is a special case of quantum channels. Hence, understanding quantum channels is equivalent to understanding time-evolutions of physical systems.

From such a point of view, I am recently attracted by the field of quantum Shannon theory and thinking about the following topics.

- Developing the decoupling approach
- Hybrid communications simultaneously transmitting quantum and classical information
- Extending the family tree of information protocols
- Quantum Shannon theory consistent with physical constraints
- Constructing decoders for random encodings

## Understanding complex quantum many-body systems

Quantum many-body systems have been always fascinating me for a long time. I especially would like to understand complex many-body systems from the quantum information theoretic viewpoint.

Although I am currently occupied by other topics, I am still interested in the following topics.

- Finite temperature entanglement in quantum spin systems
- Spin glasses and “phase transition” phenomena caused by information theoretic mechanism
- How to quantify information in complex many-body systems